My 65 Champ losing it's voice

[vintageguitars]

Hi, new here.

Hope someone can offer knowledgeable advice, I’ve been searching the internet for some clues to help my sick late 1965 Fender Champ.

I bought it used in 1967 (mint cond) and it was very healthy then and blasted out great volume and tone for being a little bugger. It is completely original in every way, a late 65 model (Fender Musical Instruments) model. Black tolex, black face.

I stored it for many years and recently pulled it out to hear it again. I was shocked to hear that it had very little volume as I turned up the volume knob from 1 – 8, and then from 9 – 10 the volume disappears! I swapped in three good tubes from another Champ I have that's not all original, with no solution to the lack of volume. I'll assume here that it's not a tube issue.

Also, the On/Off switch is failing and need replacement. Anyone know where to find a new original, or one that a perfect knockoff cheap?

I am pretty good with a soldering iron and a DVM, I would like to fix it myself if possible.

Anyone with an idea what the problem could be and how to fix my little Champ would be greatly appreciated

[stokes]

Filter caps,and tubes.General cleaning.You had it stored for years,the filter caps dry out if left for years with no voltage/current applied to them.Your old tubes may be good still,if it wasnt used a lot before being stored,but a fresh set of NOS tubes cant hurt.

[cbarrow7625]

The disappearing volume when turned from 9-10 makes me suspect that you have leaky coupling caps. If DC is leaking through the coupling caps when you turn from 9-10, the full amount of DC voltage would be going directly into the following tube. Too much positive DC voltage on the grid will bias the tube into cutoff and that = no volume.

Check from the wiper of the volume pot to ground. You should read 0VDC. If you read any DC you probably have a leaky coupling cap. You should see the DC go up & down as you turn the pot up & down if you have this problem.

Good luck.

[Paul P]

Voltages in tube amps are way higher than normal electronic stuff so before
you go measuring that voltage read up a bit on how to safely work on a tube
amp :

http://www.aikenamps.com/SafetyTips.html

You have to be extra careful when you're new to this. I've been working
on a live amp only since the last few weeks and find I have to keep going
over and over in my head what I should be doing and how. One stupid
mistake I did was when I wanted to change the leads on my DMM to measure
bias and pulled the hot lead out of the DMM while it was still connected to
B+. Thank you Fluke for making leads with recessed contacts.

Paul P

[vintageguitars]

Great people on this BBS, thanks for the input!

Hey guys -
stokes, cbarrow7625 and Paul P, thanks a bunch for the directions to take in mending my sweet lil Champ; especially the safety precaution link! I'm now in IT and the same kind of care was needed on older PC and CRT type monitor repair. I've gotten knocked on my old ass once before forgetting to discharge a couple caps in a big 21-in monitor.

Does anyone have some suggestions on who sells good vintage Fender compatible Filter Caps, Coupling Caps, On/Off Switches, etc. at nice low prices? Also who's got good tubes, NOS or new mfg? Any brands to stay away from?

Don't imagine that there's many NOS RCA and GE's around.

[Paul P]

Don't imagine that there's many NOS RCA and GE's around.

Well there are tons of NOS RCA rectifier tubes available for not much more
than new ones. I'm using new Tung-sol 6v6's (nothing to do with the NOS
ones) and haven't read anything bad about them anywhere, and quite a bit
of good. I'm also using Tung-sol 12ax7's but that's more a matter of not
knowing what else to use.

Paul P

[stokes]

For filter caps you dont want "vintage" caps or NOS,they have been sitting around for years unused,they will be dried out.I would suggest Sprague or F&T's,I dont like the cheap Asian manufacture.Try www.tubes and more.com they have them.As for tubes there are still a lot of NOS RCA,GE and many more good ones out there.If you dont want to spend the premium $$$ suppliers charge for NOS tubes you can check ebay,I've gotten plenty of good ones there for a reasonable price.

[stokes]

That link came up wrong it is www.tubesandmore.com I want to add that you should change all the electrolytics in the amp,including the smaller ones on the cathodes of your tubes

[vintageguitars]

Finding a full Cap replacement "kit"

Hey guys,
Been searching the internet for a few days, I noticed a few companies that offer rebuild kits for many vintage Fender amps, but often they also want to sell your more than just caps - including all the pots, switches, tube sockets, tubes, kitchen sink, front door, etc. etc.

As I said before, the tubes I have are in VG condition (I have another 67 Champ with fresh tubes, and I tested my 65's tubes in the 67).

I wrote one dealer www.vacuumtube.com and ask for a complete cap (including filter caps) kit for the 65 Champ. He quoted me "Probably about $60 plus shipping using US Sprague caps where approrpiate."

What do you guys with a lot more expertise think about the price and would a "complete" cap replacement kit likely do the trick?

Thanks!

[Paul P]

Depends on how much time you want to spend on this I guess. There are
I believe eleven capacitors, it would be a pretty simple matter to buy them
from a place like Mouser. This should be the schematic for your amp :

http://www.ampwares.com/ffg/schem/champ_aa764_schem.gif

Most of them are real cheap, but the filter capacitors will be the main
cost at around 7-8$ each if you want good ones (like Mallory's). Still
cheaper than the 60$ you were quoted.

I suggest you change your power cord to a proper three-wire one while
you're at it. There should be many internet sites describing how to do
this, here's one that looks ok :

http://www.theguitarfiles.com/guitarfile644.html

Have fun,

Paul P

[stokes]

I wouldnt change the coupling caps unless they are leaky.There are only about 6 electros in the Champ.3 bypass caps on the cathodes and 3 20uf filters.